1. Field of the Invention
This invention relates generally to window and door units, and more particularly to a window or door unit which incorporates means for preventing sashes or doors from becoming accidentally detached from an outer frame on which they are slidably mounted.
2. Prior Art
Many attempts have been made to prevent a sliding window installed within an outer frame from falling out of place. To this end, it is known to mount a blocking member or retainer strip on the header of the outer frame, the blocking member being disposed within a guide groove formed in the header. This arrangement has a disadvantage in that often a workman would forget about the use or presence of such blocking member because its location is such that it cannot readily be seen.